Mourinho: "I think he is one of these people who is a voyeur. He likes to watch other people. There are some guys who, when they are at home, have a big telescope to see what happens in other families. He speaks, speaks, speaks about Chelsea."

Wenger: "He’s out of order, disconnected with reality and disrespectful. When you give success to stupid people, it makes them more stupid sometimes."

Wenger threatens to take legal action against Mourinho for calling him a 'voyeur'.

Mourinho: "At Stamford Bridge, we have a file of quotes from Mr. Wenger about Chelsea football club in the last 12 months - it is not a file of five pages. It is a file of 120 pages, so we have a very strong reaction. My objective is that it is enough."

Mourinho responds by defending his strong attack of Wenger and claims to have the Frenchman's Chelsea insults on record.

APRIL 2007

Wenger: "If you would like to compare every manager you give each one the same amount of resources and say: 'you have that for five years'. After five years you see who has done the most."

'Le Professor' takes a cheeky dig at Mourinho on the eve of Chelsea's 2007 League Cup final win over Arsenal, in which John Obi Mikel, Kolo Toure and Emmanuel Adebayor were sent of for their part in an ugly brawl.

NOVEMBER 2007

Mourinho: "Unlike Arsenal, we sought success and tried to build it through a concept of the game using English players."

The 'Special One' points the finger at Wenger and Arsenal’s policy in his book.

APRIL 2008

Mourinho: "The English like statistics a lot. Do they know that Arsene Wenger has only 50 percent of wins in the English league?"

Seven months after leaving Chelsea by 'mutual consent' the Portuguese manager can't help himself but to have another swipe at Wenger.

NOVEMBER 2010

Wenger: "You never say it doesn't cross your mind but when you see how it looks on television it is the best demonstration to think: 'Never do that again'.

"It looks, frankly, horrible. It's a pity to see that from a big club."

Wenger vents his disgust at the now Real Madrid manager’s decision to get Xabi Alonso and Sergio Ramos deliberately cautioned by the referee during a Champions League match with Galatasaray.

Mourinho: "Instead of speaking about Real Madrid, Mr. Wenger should speak about Arsenal and explain how he lost 2-0 against a team in the Champions League for the first time [Braga]. The history about the young kids is getting old now. Sagna, Clichy, Walcott, Fabregas, Song, Nasri, Van Persie, Arshavin are not kids. They are all top players.

Wenger: "It is fear to fail. If you are not in a race, you cannot lose it. If you declare yourself not in the race, you cannot lose, it simple as that."

Wenger says the title is Chelsea's to lose and that Mourinho is playing down his own team's chances because of a fear of faiure.

Mourinho: "So maybe he's right, maybe I'm not used to failing, but the reality is that he's the specialist because he's had eight years without a trophy. If I do that in Chelsea I leave and I don't come back."

Mourinho responds with possibly his most hard-hitting attack yet, claiming that Wenger is a 'failure specialist'.

And so it rumbles on. The old rivalry has been sparked again, and that is certainly not going to be the end of it.